Hello Ammar,
The problem here is that you are entering a string as a search parameter while the field in the collection is of type Date/Time.
One solution to your problem is to add a afterInsertionHook to your collection that takes the created date and inserts it into another field (ie createdDateString). Then all you have to do is query this new field for the date you want.
Useful links:
AfterInsertHook - for inserting into new field
.slice() - for getting specific characters in a string
Let me know if this helps
Majd